Electronics : Electric Fence

Schematic :

Circuit :

This circuit uses two 555 timer IC's to create pulses.
The first timer, U1, is operated astable as an oscillator. U1 determines how often the pulses will be generated. There could be one pulse every ten seconds or thousands
of pulses per second.
The second timer determines the duration of the pulse.
U2 is operated as a slave to U1. U2 only emits a pulse when U1 says to do so.
U2 is a monostable multivibrator also known as a "one-shot" multivibrator.
The output stage is made by 2 transistors : the 2N222A and the 2N3055. The 2N3055 is connected to the ignition coil of a car. The exact automotive ignition coil you use is not important.
In order to function properly every electric fence needs a good
ground. Consider several grounding rods if your soil is dry. Drive the rods as far as you can into the ground and use at least 8mm wire between the charger and the ground rod.

Usage :

If you are training livestock to an electric fence, then keep the frequency high. After the livestock is wary of the fence, turn the frequency down to save power.
You can adjust the amount of power to suit your ground conditions (dry ground
has higher resistance and requires more power). You can adjust the power to suit the length of your fence. It's possible to charge up over five miles of fence in dry conditions.

CAUTIONG : THIS ELECTRIC FENCE MAKES HIGH VOLTAGE !

The basics of safety apply here. Don't let your body get between the high voltage output of the coil and ground. Turn the fence OFF if you are doing repairs. The pulse emitted by the electric fence is high in voltage, but limited in power because the pulses duration is very short.

Schematic and PCB design :

You need the Eagle CAD program to view this schematic. Download a limited edition of this program at : Eagle Soft USA